Australia has considerable wave and tidal ocean energy resources. Development of the emerging ocean renewable energy (ORE) industry in Australia offers opportunities to build Australia's blue ...economy, while actively contributing to committed carbon mitigation measures. Many interdisciplinary challenges are currently hampering development of the industry in Australia, and globally, including technology, cost reduction, policy and regulations, potential for environmental effects, awareness and investment, amongst others. In October 2016, ORE technology and project developers, researchers, academics, policy makers and other stakeholders in Australia's emerging ORE industry came together to identify these challenges and develop possible pathways to grow ocean energy in Australia. Four themes were identified: Technology Development; Education and Awareness; Policy and Regulation; and Finance and Investment. This paper documents the outcomes of the meeting identifying challenges and a way forward against each theme. A key element identified across all themes was the need for stronger coordination across the sector, and the need for a representing body to lead necessary initiatives to support growth and management of the ORE industry in Australia, as one element of a burgeoning blue economy.
•Australia should be an attractive prospect for development of ocean renewables.•Challenges and pathways to grow ocean energy in Australia are identified.•Four priority themes are Technology; Education; Policy; Investment.•Strong coordination across the Australian sector is required to motivate growth.
Sea level rise exhibits significant regional differences. Based on Coupled Model Intercomparison Project Phase 5 (CMIP5) models, sea level projections have been produced for the Australian region by ...taking account of regional dynamic changes, ocean thermal expansion, mass loss of glaciers, changes in Greenland and Antarctic ice sheets and land water storage, and glacial isostatic adjustment. However, these regional projections have a coarse resolution (~100 km), while coastal adaptation planners demand finer scale information at the coast. To address this need, a 1/10° near‐global ocean model driven by ensemble average forcings from 17 CMIP5 models is used to downscale future climate. We produce high‐resolution sea level projections by combining downscaled dynamic sea level with other contributions. Off the southeast coast, dynamic downscaling provides better representation of high sea level projections associated with gyre circulation and boundary current changes. The high‐resolution sea level projection should be a valuable product for detailed coastal adaptation planning.
Key Points
The distribution of future sea level rise around Australia results from combination of ocean dynamics, loss of land ice, and GIA
Dynamic sea level is the leading process to induce regional variations, under moderate and strong emission scenarios
Downscaling with a 1/10° OGCM produces better dynamic sea level responses from climate models, linked to ocean gyre circulation
It is essential to understand the causes of sea level extremes in order to anticipate and respond to coastal flooding (inundation), and to adapt to sea level rise. We investigate a series of ...inundation events which occurred across the western Pacific over several consecutive days during December 2008, causing severe impacts to five Pacific Island nations. These events were not associated with commonly identified causes: tropical cyclones or unusually large astronomical tides. Instead, the dissipation of wind-waves generated by distant extra-tropical cyclones (swell) was the main cause, although regional sea level variability, including recent accelerated rise, significantly contributed to the severity of impact experienced at many locations. The implication of recent sea level rise in the severity of these events suggests that episodic swell will increasingly cause major impacts of the nature described herein, although such impacts will continue to be modulated by El Niño/Southern Oscillation (ENSO) variability in the region. Significantly, tide gauges recorded little evidence of extreme sea levels during the event, implying that causes of extreme sea levels inferred from tide gauge analysis are unlikely to include this important cause of inundation. Therefore, any assessment of inundation risk predicated on tide gauge information (as well as larger scale sea level information such as satellite altimetry) may fail at many locations in the Pacific. To be accurate, such efforts must include information on the relationship between wave climate, wave forecasts and local extreme water levels. Further development of related early warning systems will become more pertinent as modern SLR continues to add to the magnitude of extremes.
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•A major inundation event impacting six Pacific island nations is documented.•Wind-waves from distant mid-latitude storms were the proximate cause.•Regional sea-level variability and rise played a significant role.•The global tide gauge network did not record the significance of this event.•The frequency and severity of such events will most likely increase in the future.
Australia is widely recognised as having an abundant wave energy resource which could contribute to the country's future energy mix. Prior assessments have provided general broad scale information on ...the resource magnitude, but detail needed to support next level site assessments has been deficient. Aiming to support all stakeholders in Australia's emerging wave energy industry, this study presents a revised assessment of Australia's national wave energy resource. The assessment is based on a state-of-the-art global wave hindcast, with higher resolution in the Australian region. Validation of the hindcast relative to in-situ wave buoy and satellite altimeter observations show better comparison than prior assessments. The total nationally available resource is similar in magnitude to earlier studies, but regional differences are evident. The total integrated energy flux across the 200 m contour is approximately 2730 TWh/yr, with estimates of resource along the north and eastern coasts being less than previously estimated. This revised pre-competitive resource information is delivered coincidently with marine management and alternative use (constraint layers), and energy infrastructure, spatial information via the open-access Australian Wave Energy Atlas (AWavEA), served through the Australian Renewable Energy Infrastructure (AREMI). The Atlas serves to reduce barriers to emergence of an Australian wave energy industry.
•Revised estimates of Australia's wave energy resource specify altered spatial distribution.•Total integrated wave energy flux across 200 m contour is 2730 TWh/yr.•Resource information being served openly via web-based Australian Wave Energy Atlas.
This paper reviews the current understanding of the effect of climate change on extreme sea levels in the South Pacific region. This region contains many locations that are vulnerable to extreme sea ...levels in the current climate, and projections indicate that this vulnerability will increase in the future. The recent publication of authoritative statements on the relationship between global warming and global sea level rise, tropical cyclones and the El Niño-Southern Oscillation phenomenon has motivated this review. Confident predictions of global mean sea level rise are modified by regional differences in the steric (density-related) component of sea level rise and changing gravitational interactions between the ocean and the ice sheets which affect the regional distribution of the eustatic (mass-related) contribution to sea level rise. The most extreme sea levels in this region are generated by tropical cyclones. The intensity of the strongest tropical cyclones is likely to increase, but many climate models project a substantial decrease in tropical cyclone numbers in this region, which may lead to an overall decrease in the total number of intense tropical cyclones. This projection, however, needs to be better quantified using improved high-resolution climate model simulations of tropical cyclones. Future changes in ENSO may lead to large regional variations in tropical cyclone incidence and sea level rise, but these impacts are also not well constrained. While storm surges from tropical cyclones give the largest sea level extremes in the parts of this region where they occur, other more frequent high sea level events can arise from swell generated by distant storms. Changes in wave climate are projected for the tropical Pacific due to anthropogenically-forced changes in atmospheric circulation. Future changes in sea level extremes will be caused by a combination of changes in mean sea level, regional sea level trends, tropical cyclone incidence and wave climate. Recommendations are given for research to increase understanding of the response of these factors to climate change. Implications of the results for adaptation research are also discussed.
Despite widespread efforts to implement climate services, there is almost no literature that systematically analyzes users' needs. This paper addresses this gap by applying a decision analysis ...perspective to identify what kind of mean sea level rise (SLR) information is needed for local coastal adaptation decisions. We first characterize these decisions, then identify suitable decision analysis approaches and the sea level information required, and finally discuss if and how these information needs can be met given the state of the art of sea level science. We find that four types of information are needed: (i) probabilistic predictions for short‐term decisions when users are uncertainty tolerant; (ii) high‐end and low‐end SLR scenarios chosen for different levels of uncertainty tolerance; (iii) upper bounds of SLR for users with a low uncertainty tolerance; and (iv) learning scenarios derived from estimating what knowledge will plausibly emerge about SLR over time. Probabilistic predictions can only be attained for the near term (i.e., 2030–2050) before SLR significantly diverges between low and high emission scenarios, for locations for which modes of climate variability are well understood and the vertical land movement contribution to local sea levels is small. Meaningful SLR upper bounds cannot be defined unambiguously from a physical perspective. Low‐ to high‐end scenarios for different levels of uncertainty tolerance and learning scenarios can be produced, but this involves both expert and user judgments. The decision analysis procedure elaborated here can be applied to other types of climate information that are required for mitigation and adaptation purposes.
Plain Language Summary
Information on future sea‐level rise (SLR) is needed for diverse coastal adaptation decisions such as deciding on how much sand to apply for counteracting beach erosion, designing the height and strength of coastal protection infrastructure, and planing future developments in the coastal zone. Different kinds of decisions thereby require different kinds of SLR information and not all kinds of information required can be delivered by the state‐of‐the‐art of sea‐level rise science. This paper addresses this problem from the points of view of both decision science and sea‐level rise science. We find that three kinds of SLR information can be produced to inform coastal decision making. First, probabilistic predictions of mean SLR can be produced for short term decisions (i.e., 2030‐2050) and some locations. Second, high‐end sea‐level rise scenarios chosen for different levels of uncertainty tolerance of decision makers can be developed by SLR experts assigning confidence levels to available SLR studies. Third, learning scenarios estimating what will be known about SLR at given points in the future can further improve decision making. The procedure elaborated in this paper can be applied to other types of climate information such as temperature or precipitation.
Key Points
Different kinds of contexts require different kinds of sea level rise information to support coastal adaptation decision making
Uncertainty intolerant users require high‐end and low‐end sea level rise scenarios produced for different levels of uncertainty intolerance
Long‐term decisions can be improved through learning scenarios estimating what will be learned about sea level rise in the future
•Statistically significant wave anomalies in the Southern Hemisphere covary with SAM surface zonal winds.•Significant wave anomalies are also detected in the central North Pacific and North Atlantic ...oceans during DJF.•The northern extratropical wave signals occur in connection with SAM teleconnections, independent of ENSO.•The SAM also influences the occurrence of daily low and high wave conditions.•The SAM may be a source of sub-weekly to seasonal predictability of surface waves.
We assess the impact of the Southern Annular Mode (SAM) on global ocean wind waves using 30 years of wave data from a wave model hindcast that is forced with high resolution surface winds from the NCEP-CFSR reanalysis. Our primary focus is on the wave field and swell influence in the Southern Hemisphere, and we apply our analysis to each of the four temperate-zone seasons comprising March–May (MAM), June–August (JJA), September-November (SON), and December–February (DJF). Statistically significant anomalies in significant wave height (Hs), peak wave period (Tp) and zonal wave energy flux (CgE) are found to covary with local variations in surface zonal wind induced by the low and high polarity phases of the SAM.
The signature of the SAM in ocean surface waves extends beyond local wind-generated forcing in the Southern Hemisphere extratropics to remote forcing in the Northern Hemisphere extratropics during DJF, with the associated atmospheric signal resembling a tropically-forced Rossby wave train. This has a significant impact on surface waves in the central North Pacific and North Atlantic oceans. The El Niño Southern Oscillation (ENSO) acts to weaken the link between the SAM and Northern Hemisphere winter climate, with the zonal wind / divergence anomalies amplifying over the tropical Pacific Ocean when we exclude El Niño and La Niña years from the analysis. This remote link to the SAM thus occurs independent of ENSO via SAM-driven changes to the tropical atmospheric circulation, suggesting that the SAM may provide a useful predictive signal for the Northern Hemisphere during DJF. The SAM also influences the occurrence of daily low (below the 5th percentile) and high (above the 95th percentile) wave conditions, emphasizing that the SAM may be a valuable source of predictable wave variability from sub-weekly to seasonal timescales. Future work should explore wave data suitable for trend analysis, considering the positive trend in the SAM over recent decades.
For many climate change impacts such as drought and heat waves, global and national frameworks for climate services are providing ever more critical support to adaptation activities. Coastal zones ...are especially in need of climate services for adaptation, as they are increasingly threatened by sea level rise and its impacts, such as submergence, flooding, shoreline erosion, salinization and wetland change. In this paper, we examine how annual to multi-decadal sea level projections can be used within coastal climate services (CCS). To this end, we review the current state-of-the art of coastal climate services in the US, Australia and France, and identify lessons learned. More broadly, we also review current barriers in the development of CCS, and identify research and development efforts for overcoming barriers and facilitating their continued growth. The latter includes: (1) research in the field of sea level, coastal and adaptation science and (2) cross-cutting research in the area of user interactions, decision making, propagation of uncertainties and overall service architecture design. We suggest that standard approaches are required to translate relative sea level information into the forms required to inform the wide range of relevant decisions across coastal management, including coastal adaptation.
Intense cyclones often result in severe impacts on mid-latitude coastal regions of southeastern Australia, including those due to associated natural hazards such as extreme winds, ocean waves, storm ...surges, precipitation, flooding, erosion, lightning and tornadoes in some cases. These low-pressure systems, known as east coast lows (ECLs), have been examined in a wide range of different studies, with considerable variations between such studies in what they consider to be an ECL, and their findings on the characteristics of these storm systems. Here we present reviews of literature and other information such as operational forecasting approaches, which are then used to produce a comprehensive synthesis of knowledge on ECLs and associated weather and ocean extremes. This includes aspects such as their definition, formation, meteorology, climatology and drivers of variability from short-term weather time scales up to long-term historical climate trends and future projections. Australian ECLs are also considered here in relation to similar phenomena from other regions of the world. A definition based on this synthesis of knowledge is as follows: ECLs are cyclones near southeastern Australia that can be caused by both mid-latitude and tropical influences over a range of levels in the atmosphere; Intense ECLs have at least one major hazard associated with their occurrence, including extreme winds, waves, rain or flooding. Knowledge gaps are examined and used to provide recommendations for future research priorities. This study is intended to lead to improved guidance and preparedness in relation to the impacts of these storms.
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